Axial support structure for a flexible elongate device

ABSTRACT

An axial support structure for a flexible elongate device includes a plurality of rigid links coupled by pin joints. Each of the plurality of rigid links comprises a shaft, a pair of male joint connectors extending axially from a first end of the shaft, and a pair of female joint connectors extending axially from a second end of the shaft opposite the first end. The female joint connectors are complementary to the male joint connectors and are rotated by 90 degrees relative to the male joint connectors. Each of the plurality of rigid links is rotated by 90 degrees with respect to neighboring links among the plurality of rigid links, thereby aligning each pair of male joint connectors with a neighboring pair of female joint connectors to form the pin joints.

RELATED APPLICATIONS

This patent application claims priority to and the benefit of the filingdate of U.S. Provisional Patent Application No. 62/378,943 entitled“Axial Support Structure for a Flexible Elongate Device,” filed Aug. 24,2016, and U.S. Provisional Patent Application No. 62/535,673 entitled“Flexible Elongate Devices and Methods,” filed Jul. 21, 2017.

TECHNICAL FIELD

The present disclosure is directed to a support structure for anelongate device and more particularly to a linked axial supportstructure for a flexible elongate device.

BACKGROUND

Minimally invasive medical techniques are intended to reduce the amountof tissue that is damaged during medical procedures, thereby reducingpatient recovery time, discomfort, and harmful side effects. Suchminimally invasive techniques may be performed through natural orificesin a patient anatomy or through one or more surgical incisions. Throughthese natural orifices or incisions physician may insert minimallyinvasive medical instruments (including surgical, diagnostic,therapeutic, or biopsy instruments) to reach a target tissue location.One such minimally invasive technique is to use a flexible and/orsteerable elongate device, such as a flexible catheter, that can beinserted into anatomic passageways and navigated toward a region ofinterest within the patient anatomy. In some applications, the flexibleand/or steerable elongate device is subjected to axial loads duringoperation (e.g., pulling and/or pushing forces along an axial directionof the elongate device). If the axial loads exceed the axial strength ofthe elongate device, the elongate device and/or medical instruments maybe damaged and the patient may be injured.

Accordingly, it would be advantageous to provide axial supportstructures for flexible and/or steerable elongate devices, such assteerable catheters, that are suitable for use during minimally invasivemedical techniques.

SUMMARY

The embodiments of the invention are best summarized by the claims thatfollow the description.

In some embodiments, an axial support structure for a flexible elongatedevice includes a plurality of rigid links coupled by pin joints. Eachof the plurality of rigid links comprises a shaft, a pair of male jointconnectors extending axially from a first end of the shaft, and a pairof female joint connectors extending axially from a second end of theshaft opposite the first end. The female joint connectors arecomplementary to the male joint connectors and are rotated by 90 degreesrelative to the male joint connectors. Each of the plurality of rigidlinks is rotated by 90 degrees with respect to neighboring links amongthe plurality of rigid links, thereby aligning each pair of male jointconnectors with a neighboring pair of female joint connectors to formthe pin joints.

In some embodiments, an axially reinforced flexible body includes apliable tube and an axial support structure disposed within the pliabletube. The axial support structure includes a plurality of rigid linkscoupled by pin joints. Each of the plurality of rigid links includes ashaft, a set of male joint connectors extending in an axial directionfrom a first end of the shaft, and a set of female joint connectorsextending in the axial direction from a second end of the shaft oppositethe first end. The set of female joint connectors are complementary tothe set of male joint connectors and are rotated by 90 degrees relativeto the set of male joint connectors. Each of the plurality of rigidlinks is rotated by 90 degrees with respect to neighboring links amongthe plurality of rigid links, thereby aligning each set of male jointconnectors with a neighboring set of female joint connectors to form thepin joints.

In some embodiments, a method for fabricating an axially reinforcedflexible body includes forming a plurality of rigid links, coupling theplurality of rigid links to form an axial support structure, andencapsulating the axial support structure in a pliable tube to form anaxially reinforced flexible body. Each of the plurality of rigid linksincludes a shaft, a set of male joint connectors extending axially froma first end of the shaft, and a set of female joint connectors extendingaxially from a second end of the shaft opposite the first end. The setof female joint connectors are complementary to the set of male jointconnectors and are rotated by 90 degrees relative to the set of malejoint connectors. Each of the plurality of rigid links is rotated by 90degrees with respect to neighboring links among the plurality of rigidlinks, thereby aligning each set of male joint connectors with aneighboring set of female joint connectors to form pin joints.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory innature and are intended to provide an understanding of the presentdisclosure without limiting the scope of the present disclosure. In thatregard, additional aspects, features, and advantages of the presentdisclosure will be apparent to one skilled in the art from the followingdetailed description.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a simplified diagram of a teleoperated medical systemaccording to some embodiments.

FIG. 2A is a simplified diagram of a medical instrument system accordingto some embodiments.

FIG. 2B is a simplified diagram of a medical instrument with an extendedmedical tool according to some embodiments.

FIGS. 3A and 3B are simplified diagrams of side views of a patientcoordinate space including a medical instrument mounted on an insertionassembly according to some embodiments.

FIG. 4 is a simplified diagram of an axial support structure accordingto some embodiments.

FIGS. 5A and 5B are simplified diagrams of an axially reinforcedflexible body according to some embodiments.

FIGS. 6A-D are simplified diagrams of a rigid link for an axial supportstructure according to some embodiments.

FIG. 7 is a simplified diagram of a method for fabricating an axiallyreinforced flexible body according to some embodiments.

Embodiments of the present disclosure and their advantages are bestunderstood by referring to the detailed description that follows. Itshould be appreciated that like reference numerals are used to identifylike elements illustrated in one or more of the figures, whereinshowings therein are for purposes of illustrating embodiments of thepresent disclosure and not for purposes of limiting the same.

DETAILED DESCRIPTION

In the following description, specific details are set forth describingsome embodiments consistent with the present disclosure. Numerousspecific details are set forth in order to provide a thoroughunderstanding of the embodiments. It will be apparent, however, to oneskilled in the art that some embodiments may be practiced without someor all of these specific details. The specific embodiments disclosedherein are meant to be illustrative but not limiting. One skilled in theart may realize other elements that, although not specifically describedhere, are within the scope and the spirit of this disclosure. Inaddition, to avoid unnecessary repetition, one or more features shownand described in association with one embodiment may be incorporatedinto other embodiments unless specifically described otherwise or if theone or more features would make an embodiment non-functional.

In some instances well known methods, procedures, components, andcircuits have not been described in detail so as not to unnecessarilyobscure aspects of the embodiments.

This disclosure describes various instruments and portions ofinstruments in terms of their state in three-dimensional space. As usedherein, the term “position” refers to the location of an object or aportion of an object in a three-dimensional space (e.g., three degreesof translational freedom along Cartesian x-, y-, and z-coordinates). Asused herein, the term “orientation” refers to the rotational placementof an object or a portion of an object (three degrees of rotationalfreedom—e.g., roll, pitch, and yaw). As used herein, the term “pose”refers to the position of an object or a portion of an object in atleast one degree of translational freedom and to the orientation of thatobject or portion of the object in at least one degree of rotationalfreedom (up to six total degrees of freedom). As used herein, the term“shape” refers to a set of poses, positions, or orientations measuredalong an object.

FIG. 1 is a simplified diagram of a teleoperated medical system 100according to some embodiments. In some embodiments, teleoperated medicalsystem 100 may be suitable for use in, for example, surgical,diagnostic, therapeutic, or biopsy procedures. As shown in FIG. 1 ,medical system 100 generally includes a teleoperational manipulatorassembly 102 for operating a medical instrument 104 in performingvarious procedures on a patient P. Teleoperational manipulator assembly102 is mounted to or near an operating table T. A master assembly 106allows an operator (e.g., a surgeon, a clinician, or a physician O asillustrated in FIG. 1 ) to view the interventional site and to controlteleoperational manipulator assembly 102.

Master assembly 106 may be located at a physician's console which isusually located in the same room as operating table T, such as at theside of a surgical table on which patient P is located. However, itshould be understood that physician O can be located in a different roomor a completely different building from patient P. Master assembly 106generally includes one or more control devices for controllingteleoperational manipulator assembly 102. The control devices mayinclude any number of a variety of input devices, such as joysticks,trackballs, data gloves, trigger-guns, hand-operated controllers, voicerecognition devices, body motion or presence sensors, and/or the like.To provide physician O a strong sense of directly controllinginstruments 104 the control devices may be provided with the samedegrees of freedom as the associated medical instrument 104. In thismanner, the control devices provide physician O with telepresence or theperception that the control devices are integral with medicalinstruments 104.

In some embodiments, the control devices may have more or fewer degreesof freedom than the associated medical instrument 104 and still providephysician O with telepresence. In some embodiments, the control devicesmay optionally be manual input devices which move with six degrees offreedom, and which may also include an actuatable handle for actuatinginstruments (for example, for closing grasping jaws, applying anelectrical potential to an electrode, delivering a medicinal treatment,and/or the like).

Teleoperational manipulator assembly 102 supports medical instrument 104and may include a kinematic structure of one or more non-servocontrolled links (e.g., one or more links that may be manuallypositioned and locked in place, generally referred to as a set-upstructure) and a teleoperational manipulator. Teleoperationalmanipulator assembly 102 may optionally include a plurality of actuatorsor motors that drive inputs on medical instrument 104 in response tocommands from the control system (e.g., a control system 112). Theactuators may optionally include drive systems that when coupled tomedical instrument 104 may advance medical instrument 104 into anaturally or surgically created anatomic orifice. Other drive systemsmay move the distal end of medical instrument 104 in multiple degrees offreedom, which may include three degrees of linear motion (e.g., linearmotion along the X, Y, Z Cartesian axes) and in three degrees ofrotational motion (e.g., rotation about the X, Y, Z Cartesian axes).Additionally, the actuators can be used to actuate an articulable endeffector of medical instrument 104 for grasping tissue in the jaws of abiopsy device and/or the like. Actuator position sensors such asresolvers, encoders, potentiometers, and other mechanisms may providesensor data to medical system 100 describing the rotation andorientation of the motor shafts. This position sensor data may be usedto determine motion of the objects manipulated by the actuators.

Teleoperated medical system 100 may include a sensor system 108 with oneor more sub-systems for receiving information about the instruments ofteleoperational manipulator assembly 102. Such sub-systems may include aposition/location sensor system (e.g., an electromagnetic (EM) sensorsystem); a shape sensor system for determining the position,orientation, speed, velocity, pose, and/or shape of a distal end and/orof one or more segments along a flexible body that may make up medicalinstrument 104; and/or a visualization system for capturing images fromthe distal end of medical instrument 104.

Teleoperated medical system 100 also includes a display system 110 fordisplaying an image or representation of the surgical site and medicalinstrument 104 generated by sub-systems of sensor system 108. Displaysystem 110 and master assembly 106 may be oriented so physician O cancontrol medical instrument 104 and master assembly 106 with theperception of telepresence.

In some embodiments, medical instrument 104 may have a visualizationsystem (discussed in more detail below), which may include a viewingscope assembly that records a concurrent or real-time image of asurgical site and provides the image to the operator or physician Othrough one or more displays of medical system 100, such as one or moredisplays of display system 110. The concurrent image may be, forexample, a two or three dimensional image captured by an endoscopepositioned within the surgical site. In some embodiments, thevisualization system includes endoscopic components that may beintegrally or removably coupled to medical instrument 104. However insome embodiments, a separate endoscope, attached to a separatemanipulator assembly may be used with medical instrument 104 to imagethe surgical site. The visualization system may be implemented ashardware, firmware, software or a combination thereof which interactwith or are otherwise executed by one or more computer processors, whichmay include the processors of a control system 112.

Display system 110 may also display an image of the surgical site andmedical instruments captured by the visualization system. In someexamples, teleoperated medical system 100 may configure medicalinstrument 104 and controls of master assembly 106 such that therelative positions of the medical instruments are similar to therelative positions of the eyes and hands of physician O. In this mannerphysician O can manipulate medical instrument 104 and the hand controlas if viewing the workspace in substantially true presence. By truepresence, it is meant that the presentation of an image is a trueperspective image simulating the viewpoint of a physician that isphysically manipulating medical instrument 104.

In some examples, display system 110 may present images of a surgicalsite recorded pre-operatively or intra-operatively using image data fromimaging technology such as, computed tomography (CT), magnetic resonanceimaging (MRI), fluoroscopy, thermography, ultrasound, optical coherencetomography (OCT), thermal imaging, impedance imaging, laser imaging,nanotube X-ray imaging, and/or the like. The pre-operative orintra-operative image data may be presented as two-dimensional,three-dimensional, or four-dimensional (including e.g., time based orvelocity based information) images and/or as images from models createdfrom the pre-operative or intra-operative image data sets.

In some embodiments, often for purposes of imaged guided surgicalprocedures, display system 110 may display a virtual navigational imagein which the actual location of medical instrument 104 is registered(i.e., dynamically referenced) with the preoperative or concurrentimages/model. This may be done to present the physician O with a virtualimage of the internal surgical site from a viewpoint of medicalinstrument 104. In some examples, the viewpoint may be from a tip ofmedical instrument 104. An image of the tip of medical instrument 104and/or other graphical or alphanumeric indicators may be superimposed onthe virtual image to assist physician O controlling medical instrument104. In some examples, medical instrument 104 may not be visible in thevirtual image.

In some embodiments, display system 110 may display a virtualnavigational image in which the actual location of medical instrument104 is registered with preoperative or concurrent images to present thephysician O with a virtual image of medical instrument 104 within thesurgical site from an external viewpoint. An image of a portion ofmedical instrument 104 or other graphical or alphanumeric indicators maybe superimposed on the virtual image to assist physician O in thecontrol of medical instrument 104. As described herein, visualrepresentations of data points may be rendered to display system 110.For example, measured data points, moved data points, registered datapoints, and other data points described herein may be displayed ondisplay system 110 in a visual representation. The data points may bevisually represented in a user interface by a plurality of points ordots on display system 110 or as a rendered model, such as a mesh orwire model created based on the set of data points. In some examples,the data points may be color coded according to the data they represent.In some embodiments, a visual representation may be refreshed in displaysystem 110 after each processing operation has been implemented to alterdata points.

Teleoperated medical system 100 may also include control system 112.Control system 112 includes at least one memory and at least onecomputer processor (not shown) for effecting control between medicalinstrument 104, master assembly 106, sensor system 108, and displaysystem 110. Control system 112 also includes programmed instructions(e.g., a non-transitory machine-readable medium storing theinstructions) to implement some or all of the methods described inaccordance with aspects disclosed herein, including instructions forproviding information to display system 110. While control system 112 isshown as a single block in the simplified schematic of FIG. 1 , thesystem may include two or more data processing circuits with one portionof the processing optionally being performed on or adjacent toteleoperational manipulator assembly 102, another portion of theprocessing being performed at master assembly 106, and/or the like. Theprocessors of control system 112 may execute instructions comprisinginstruction corresponding to processes disclosed herein and described inmore detail below. Any of a wide variety of centralized or distributeddata processing architectures may be employed. Similarly, the programmedinstructions may be implemented as a number of separate programs orsubroutines, or they may be integrated into a number of other aspects ofthe teleoperational systems described herein. In one embodiment, controlsystem 112 supports wireless communication protocols such as Bluetooth,IrDA, HomeRF, IEEE 802.11, DECT, and Wireless Telemetry.

In some embodiments, control system 112 may receive force and/or torquefeedback from medical instrument 104. Responsive to the feedback,control system 112 may transmit signals to master assembly 106. In someexamples, control system 112 may transmit signals instructing one ormore actuators of teleoperational manipulator assembly 102 to movemedical instrument 104. Medical instrument 104 may extend into aninternal surgical site within the body of patient P via openings in thebody of patient P. Any suitable conventional and/or specializedactuators may be used. In some examples, the one or more actuators maybe separate from, or integrated with, teleoperational manipulatorassembly 102. In some embodiments, the one or more actuators andteleoperational manipulator assembly 102 are provided as part of ateleoperational cart positioned adjacent to patient P and operatingtable T.

Control system 112 may optionally further include a virtualvisualization system to provide navigation assistance to physician Owhen controlling medical instrument 104 during an image-guided surgicalprocedure. Virtual navigation using the virtual visualization system maybe based upon reference to an acquired preoperative or intraoperativedataset of anatomic passageways. The virtual visualization systemprocesses images of the surgical site imaged using imaging technologysuch as computerized tomography (CT), magnetic resonance imaging (MRI),fluoroscopy, thermography, ultrasound, optical coherence tomography(OCT), thermal imaging, impedance imaging, laser imaging, nanotube X-rayimaging, and/or the like. Software, which may be used in combinationwith manual inputs, is used to convert the recorded images intosegmented two dimensional or three dimensional composite representationof a partial or an entire anatomic organ or anatomic region. An imagedata set is associated with the composite representation. The compositerepresentation and the image data set describe the various locations andshapes of the passageways and their connectivity. The images used togenerate the composite representation may be recorded preoperatively orintra-operatively during a clinical procedure. In some embodiments, avirtual visualization system may use standard representations (i.e., notpatient specific) or hybrids of a standard representation and patientspecific data. The composite representation and any virtual imagesgenerated by the composite representation may represent the staticposture of a deformable anatomic region during one or more phases ofmotion (e.g., during an inspiration/expiration cycle of a lung).

During a virtual navigation procedure, sensor system 108 may be used tocompute an approximate location of medical instrument 104 with respectto the anatomy of patient P. The location can be used to produce bothmacro-level (external) tracking images of the anatomy of patient P andvirtual internal images of the anatomy of patient P. The system mayimplement one or more electromagnetic (EM) sensor, fiber optic sensors,and/or other sensors to register and display a medical implementtogether with preoperatively recorded surgical images, such as thosefrom a virtual visualization system, are known. For example U.S. patentapplication Ser. No. 13/107,562 (filed May 13, 2011) (disclosing“Medical System Providing Dynamic Registration of a Model of an AnatomicStructure for Image-Guided Surgery”) which is incorporated by referenceherein in its entirety, discloses one such system. Teleoperated medicalsystem 100 may further include optional operations and support systems(not shown) such as illumination systems, steering control systems,irrigation systems, and/or suction systems. In some embodiments,teleoperated medical system 100 may include more than oneteleoperational manipulator assembly and/or more than one masterassembly. The exact number of teleoperational manipulator assemblieswill depend on the surgical procedure and the space constraints withinthe operating room, among other factors. Master assembly 106 may becollocated or they may be positioned in separate locations. Multiplemaster assemblies allow more than one operator to control one or moreteleoperational manipulator assemblies in various combinations.

FIG. 2A is a simplified diagram of a medical instrument system 200according to some embodiments. In some embodiments, medical instrumentsystem 200 may be used as medical instrument 104 in an image-guidedmedical procedure performed with teleoperated medical system 100. Insome examples, medical instrument system 200 may be used fornon-teleoperational exploratory procedures or in procedures involvingtraditional manually operated medical instruments, such as endoscopy.Optionally medical instrument system 200 may be used to gather (i.e.,measure) a set of data points corresponding to locations within anatomicpassageways of a patient, such as patient P.

Medical instrument system 200 includes elongate device 202 coupled to adrive unit 204. Elongate device 202 includes a flexible body 216 havingproximal end 217 and distal end or tip portion 218. In some embodiments,flexible body 216 has an approximately 3 mm outer diameter. Otherflexible body outer diameters may be larger or smaller.

Medical instrument system 200 further includes a tracking system 230 fordetermining the position, orientation, speed, velocity, pose, and/orshape of flexible body 216 at distal end 218 and/or of one or moresegments 224 along flexible body 216 using one or more sensors and/orimaging devices as described in further detail below. The entire lengthof flexible body 216, between distal end 218 and proximal end 217, maybe effectively divided into segments 224. If medical instrument system200 is consistent with medical instrument 104 of a teleoperated medicalsystem 100, tracking system 230. Tracking system 230 may optionally beimplemented as hardware, firmware, software or a combination thereofwhich interact with or are otherwise executed by one or more computerprocessors, which may include the processors of control system 112 inFIG. 1 .

Tracking system 230 may optionally track distal end 218 and/or one ormore of the segments 224 using a shape sensor 222. Shape sensor 222 mayoptionally include an optical fiber aligned with flexible body 216(e.g., provided within an interior channel (not shown) or mountedexternally). In one embodiment, the optical fiber has a diameter ofapproximately 200 μm. In other embodiments, the dimensions may be largeror smaller. The optical fiber of shape sensor 222 forms a fiber opticbend sensor for determining the shape of flexible body 216. In onealternative, optical fibers including Fiber Bragg Gratings (FBGs) areused to provide strain measurements in structures in one or moredimensions. Various systems and methods for monitoring the shape andrelative position of an optical fiber in three dimensions are describedin U.S. patent application Ser. No. 11/180,389 (filed Jul. 13, 2005)(disclosing “Fiber optic position and shape sensing device and methodrelating thereto”); U.S. patent application Ser. No. 12/047,056 (filedon Jul. 16, 2004) (disclosing “Fiber-optic shape and relative positionsensing”); and U.S. Pat. No. 6,389,187 (filed on Jun. 17, 1998)(disclosing “Optical Fiber Bend Sensor”), which are all incorporated byreference herein in their entireties. Sensors in some embodiments mayemploy other suitable strain sensing techniques, such as Rayleighscattering, Raman scattering, Brillouin scattering, and Fluorescencescattering. In some embodiments, the shape of flexible body 216 may bedetermined using other techniques. For example, a history of the distalend pose of flexible body 216 can be used to reconstruct the shape offlexible body 216 over the interval of time. In some embodiments,tracking system 230 may optionally and/or additionally track distal end218 using a position sensor system 220. Position sensor system 220 maybe a component of an EM sensor system with positional sensor system 220including one or more conductive coils that may be subjected to anexternally generated electromagnetic field. Each coil of EM sensorsystem 220 then produces an induced electrical signal havingcharacteristics that depend on the position and orientation of the coilrelative to the externally generated electromagnetic field. In someembodiments, position sensor system 220 may be configured and positionedto measure six degrees of freedom, e.g., three position coordinates X,Y, Z and three orientation angles indicating pitch, yaw, and roll of abase point or five degrees of freedom, e.g., three position coordinatesX, Y, Z and two orientation angles indicating pitch and yaw of a basepoint. Further description of a position sensor system is provided inU.S. Pat. No. 6,380,732 (filed Aug. 11, 1999) (disclosing “Six-Degree ofFreedom Tracking System Having a Passive Transponder on the Object BeingTracked”), which is incorporated by reference herein in its entirety.

In some embodiments, tracking system 230 may alternately and/oradditionally rely on historical pose, position, or orientation datastored for a known point of an instrument system along a cycle ofalternating motion, such as breathing. This stored data may be used todevelop shape information about flexible body 216. In some examples, aseries of positional sensors (not shown), such as electromagnetic (EM)sensors similar to the sensors in position sensor 220 may be positionedalong flexible body 216 and then used for shape sensing. In someexamples, a history of data from one or more of these sensors takenduring a procedure may be used to represent the shape of elongate device202, particularly if an anatomic passageway is generally static.

Flexible body 216 includes a channel 221 sized and shaped to receive amedical instrument 226. FIG. 2B is a simplified diagram of flexible body216 with medical instrument 226 extended according to some embodiments.In some embodiments, medical instrument 226 may be used for proceduressuch as surgery, biopsy, ablation, illumination, irrigation, or suction.Medical instrument 226 can be deployed through channel 221 of flexiblebody 216 and used at a target location within the anatomy. Medicalinstrument 226 may include, for example, image capture probes, biopsyinstruments, laser ablation fibers, and/or other surgical, diagnostic,or therapeutic tools. Medical tools may include end effectors having asingle working member such as a scalpel, a blunt blade, an opticalfiber, an electrode, and/or the like. Other end effectors may include,for example, forceps, graspers, scissors, clip appliers, and/or thelike. Other end effectors may further include electrically activated endeffectors such as electrosurgical electrodes, transducers, sensors,and/or the like. In various embodiments, medical instrument 226 is abiopsy instrument, which may be used to remove sample tissue or asampling of cells from a target anatomic location. Medical instrument226 may be used with an image capture probe also within flexible body216. In various embodiments, medical instrument 226 may be an imagecapture probe that includes a distal portion with a stereoscopic ormonoscopic camera at or near distal end 218 of flexible body 216 forcapturing images (including video images) that are processed by avisualization system 231 for display and/or provided to tracking system230 to support tracking of distal end 218 and/or one or more of thesegments 224. The image capture probe may include a cable coupled to thecamera for transmitting the captured image data. In some examples, theimage capture instrument may be a fiber-optic bundle, such as afiberscope, that couples to visualization system 231. The image captureinstrument may be single or multi-spectral, for example capturing imagedata in one or more of the visible, infrared, and/or ultravioletspectrums. Alternatively, medical instrument 226 may itself be the imagecapture probe. Medical instrument 226 may be advanced from the openingof channel 221 to perform the procedure and then retracted back into thechannel when the procedure is complete. Medical instrument 226 may beremoved from proximal end 217 of flexible body 216 or from anotheroptional instrument port (not shown) along flexible body 216.

Medical instrument 226 may additionally house cables, linkages, or otheractuation controls (not shown) that extend between its proximal anddistal ends to controllably the bend distal end of medical instrument226. Steerable instruments are described in detail in U.S. Pat. No.7,316,681 (filed on Oct. 4, 2005) (disclosing “Articulated SurgicalInstrument for Performing Minimally Invasive Surgery with EnhancedDexterity and Sensitivity”) and U.S. patent application Ser. No.12/286,644 (filed Sep. 30, 2008) (disclosing “Passive Preload andCapstan Drive for Surgical Instruments”), which are incorporated byreference herein in their entireties.

Flexible body 216 may also house cables, linkages, or other steeringcontrols (not shown) that extend between drive unit 204 and distal end218 to controllably bend distal end 218 as shown, for example, by brokendashed line depictions 219 of distal end 218. In some examples, at leastfour cables are used to provide independent “up-down” steering tocontrol a pitch of distal end 218 and “left-right” steering to control ayaw of distal end 281. Steerable catheters are described in detail inU.S. patent application Ser. No. 13/274,208 (filed Oct. 14, 2011)(disclosing “Catheter with Removable Vision Probe”), which isincorporated by reference herein in its entirety. In embodiments inwhich medical instrument system 200 is actuated by a teleoperationalassembly, drive unit 204 may include drive inputs that removably coupleto and receive power from drive elements, such as actuators, of theteleoperational assembly. In some embodiments, medical instrument system200 may include gripping features, manual actuators, or other componentsfor manually controlling the motion of medical instrument system 200.Elongate device 202 may be steerable or, alternatively, the system maybe non-steerable with no integrated mechanism for operator control ofthe bending of distal end 218. In some examples, one or more lumens,through which medical instruments can be deployed and used at a targetsurgical location, are defined in the walls of flexible body 216.

In some embodiments, medical instrument system 200 may include aflexible bronchial instrument, such as a bronchoscope or bronchialcatheter, for use in examination, diagnosis, biopsy, or treatment of alung. Medical instrument system 200 is also suited for navigation andtreatment of other tissues, via natural or surgically created connectedpassageways, in any of a variety of anatomic systems, including thecolon, the intestines, the kidneys and kidney calices, the brain, theheart, the circulatory system including vasculature, and/or the like.

The information from tracking system 230 may be sent to a navigationsystem 232 where it is combined with information from visualizationsystem 231 and/or the preoperatively obtained models to provide thephysician, clinician, or surgeon or other operator with real-timeposition information. In some examples, the real-time positioninformation may be displayed on display system 110 of FIG. 1 for use inthe control of medical instrument system 200. In some examples, controlsystem 116 of FIG. 1 may utilize the position information as feedbackfor positioning medical instrument system 200. Various systems for usingfiber optic sensors to register and display a surgical instrument withsurgical images are provided in U.S. patent application Ser. No.13/107,562, filed May 13, 2011, disclosing, “Medical System ProvidingDynamic Registration of a Model of an Anatomic Structure forImage-Guided Surgery,” which is incorporated by reference herein in itsentirety.

In some examples, medical instrument system 200 may be teleoperatedwithin medical system 100 of FIG. 1 . In some embodiments,teleoperational manipulator assembly 102 of FIG. 1 may be replaced bydirect operator control. In some examples, the direct operator controlmay include various handles and operator interfaces for hand-heldoperation of the instrument.

FIGS. 3A and 3B are simplified diagrams of side views of a patientcoordinate space including a medical instrument mounted on an insertionassembly according to some embodiments. As shown in FIGS. 3A and 3B, asurgical environment 300 includes a patient P is positioned on platform302. Patient P may be stationary within the surgical environment in thesense that gross patient movement is limited by sedation, restraint,and/or other means. Cyclic anatomic motion including respiration andcardiac motion of patient P may continue, unless patient is asked tohold his or her breath to temporarily suspend respiratory motion.Accordingly, in some embodiments, data may be gathered at a specific,phase in respiration, and tagged and identified with that phase. In someembodiments, the phase during which data is collected may be inferredfrom physiological information collected from patient P. Within surgicalenvironment 300, a point gathering instrument 304 is coupled to aninstrument carriage 306. In some embodiments, point gathering instrument304 may use EM sensors, shape-sensors, and/or other sensor modalities.Instrument carriage 306 is mounted to an insertion stage 308 fixedwithin surgical environment 300. Alternatively, insertion stage 308 maybe movable but have a known location (e.g., via a tracking sensor orother tracking device) within surgical environment 300. Instrumentcarriage 306 may be a component of a teleoperational manipulatorassembly (e.g., teleoperational manipulator assembly 102) that couplesto point gathering instrument 304 to control insertion motion (i.e.,motion along the A axis) and, optionally, motion of a distal end 318 ofan elongate device 310 in multiple directions including yaw, pitch, androll. Instrument carriage 306 or insertion stage 308 may includeactuators, such as servomotors, (not shown) that control motion ofinstrument carriage 306 along insertion stage 308.

Elongate device 310 is coupled to an instrument body 312. Instrumentbody 312 is coupled and fixed relative to instrument carriage 306. Insome embodiments, an optical fiber shape sensor 314 is fixed at aproximal point 316 on instrument body 312. In some embodiments, proximalpoint 316 of optical fiber shape sensor 314 may be movable along withinstrument body 312 but the location of proximal point 316 may be known(e.g., via a tracking sensor or other tracking device). Shape sensor 314measures a shape from proximal point 316 to another point such as distalend 318 of elongate device 310. Point gathering instrument 304 may besubstantially similar to medical instrument system 200.

A position measuring device 320 provides information about the positionof instrument body 312 as it moves on insertion stage 308 along aninsertion axis A. Position measuring device 320 may include resolvers,encoders, potentiometers, and/or other sensors that determine therotation and/or orientation of the actuators controlling the motion ofinstrument carriage 306 and consequently the motion of instrument body312. In some embodiments, insertion stage 308 is linear. In someembodiments, insertion stage 308 may be curved or have a combination ofcurved and linear sections.

FIG. 3A shows instrument body 312 and instrument carriage 306 in aretracted position along insertion stage 308. In this retractedposition, proximal point 316 is at a position L0 on axis A. In thisposition along insertion stage 308 an A component of the location ofproximal point 316 may be set to a zero and/or another reference valueto provide a base reference to describe the position of instrumentcarriage 306, and thus proximal point 316, on insertion stage 308. Withthis retracted position of instrument body 312 and instrument carriage306, distal end 318 of elongate device 310 may be positioned just insidean entry orifice of patient P. Also in this position, position measuringdevice 320 may be set to a zero and/or the another reference value(e.g., I=0). In FIG. 3B, instrument body 312 and instrument carriage 306have advanced along the linear track of insertion stage 308 and distalend 318 of elongate device 310 has advanced into patient P. In thisadvanced position, the proximal point 316 is at a position L1 on theaxis A. In some examples, encoder and/or other position data from one ormore actuators controlling movement of instrument carriage 306 alonginsertion stage 308 and/or one or more position sensors associated withinstrument carriage 306 and/or insertion stage 308 is used to determinethe position Lx of proximal point 316 relative to position L0. In someexamples, position LX may further be used as an indicator of thedistance or insertion depth to which distal end 318 of elongate device310 is inserted into the passageways of the anatomy of patient P.

FIG. 4 is a simplified diagram of an axial support structure 400according to some embodiments. According to some embodiments consistentwith FIGS. 1-3 , axial support structure 400 may be incorporated into aflexible elongate device, such as elongate device 202 and/or flexiblebody 216. According to some embodiments, axial support structure 400 maybe incorporated into a steerable portion of the flexible elongatedevice. For example, the steerable portion of the flexible elongatedevice may be controlled using one or more pull wires that generateaxial loads on the flexible elongate device during operation. Consistentwith such embodiments, axial support structure 400 may support theflexible elongate device against the axial loads generated by the one ormore pull wires. In particular, axial support structure 400 may preventor reduce distortion, compression and/or collapse of the flexibleelongate device while retaining its flexibility and/or steerability.

Axial support structure 400 is composed of a plurality of rigid links411-419. Rigid links 411-419 are coupled to each other by pin joints421-429. According to some embodiments, each of rigid links 411-419 maybe identical to one another to facilitate manufacturability and/or toreduce production costs. That is, axial support structure 400 mayconsist of a single repeated component that is easy to manufacture inbulk, inspect, replace, and/or the like. This tends to reducemanufacturing and/or operational complexity relative to other types ofsupport structures that include multiple different components. Accordingto some embodiments, rigid links 411-419 may be made of materials thatare generally more rigid and/or cheaper than those used in other typesof support structures. For example, rigid links 411-419 may be composedof stainless steel instead of a more expensive material such as nitinol.In an alternative embodiment, the axial support structure 400 may notrequire a high rigidity provided by metals such as stainless steel sorigid links 411-419 may be composed of an even lower cost plastic orthermoplastic materials such as Polyether ether ketone (PEEK), ULTEM,other thermoplastics with high melting points, and/or the like.Particular embodiments of rigid links 411-419 are described in greaterdetail below with reference to FIGS. 6A-6D.

Adjacent pairs of rigid links 411-419 are rotated by 90 degrees withrespect to each other. Consequently, adjacent pairs of pin joints421-429 pivot about perpendicular axes. This arrangement provides atleast two degrees of freedom to axial support structure 400. In thismanner, axial support structure 400 may be flexed in any direction.

A channel 430 through axial support structure 400 allows one or moremedical instruments to be inserted through axial support structure 400.Additionally or alternately, one or more pull wires, fibers (e.g.,optical fibers), cables (e.g., electrical cables), fluids, and/or thelike may be inserted into channel 430. As depicted in FIG. 4 , channel430 is enclosed by rigid links 411-419, which serve to reinforce thewalls of channel 430. According to some embodiments, reinforcing thewalls of channel 430 may protect against pull-through, which occurs whenpull wires (and/or other inserted devices) chafe against and eventuallypull through the walls of the flexible elongate device.

According to some embodiments, it may be desirable for channel 430 to bewide in order to increase the capacity of channel 430. At the same time,it may be desirable for the outer diameter of the flexible elongatedevice to be narrow to facilitate insertion into narrow anatomicalpassageways. To balance the desire for a wide channel 430 and a narrowouter diameter, axial support structure 400 may have thin walls (e.g., 1mm or less). For example, the walls of axial support structure 400 maybe as thin as possible while providing the desired level of axialstrength and/or wall reinforcement strength. In comparison, other typesof support structures, such as braided support structures, may generallyhave greater wall thickness than axial support structure 400 due to, forexample, overlapping braids.

Axial support structure 400 has a cross-sectional shape that isapproximately rectangular. While other types of support structures maybe designed to maintain a circular cross section, it is observed thatmany anatomical passageways are relatively conformable and therefore arecapable of accommodating devices with non-circular cross-sections.Accordingly, the rectangular cross-section of axial support structure400 is not generally regarded as being problematic for manyapplications. In some applications, the rectangular cross-section ofaxial support structure 400 is advantageous because the rectangularshape facilitates efficient packing of channel 430. For example, a largecircular device (e.g., a medical instrument with a circularcross-section) may occupy the center of channel 430, and one or moresmaller devices (e.g., pull wires, optical fibers, and/or electricalcables) may be inserted through unoccupied regions near the four cornersof channel 430.

According to some embodiments, axial support structure 400 may bestronger against axial loads than other types of support structures. Inparticular, the axial strength of axial support structure 400 isprovided primarily by rigid links 411-419 while the flexibility isprovided primarily by pin joints 421-429. Separating the functionalityin this manner allows axial support structure 400 to be constructedwithout a tradeoff between axial strength and flexibility. By contrast,other types of support structures, such as nitinol flexures, rely on thesame features to provide both axial strength and flexibility, resultingin a design tradeoff. For example, increasing the thickness of a nitinolflexure increases axial strength but reduces flexibility, and viceversa.

Advantageously, axial support structure 400 is capable of providing asmuch axial strength as demanded by a particular application withoutsignificantly reducing flexibility. As a result, axial support structure400 may be suitable for use in an expanded range of applicationsrelative to other types of support structures. For example, axialsupport structure 400 may be used to support flexible elongate deviceswith multiple steerable portions, which have more pull wires (andcorrespondingly greater axial loads) than flexible elongate devices witha single steerable portion. Likewise, axial support structure may beused when an end effector of the flexible elongate device generatesaxial loads during operation. For example, jaws positioned at the distalend of the flexible elongate device may be actuated using pull wiresthat generate axial loads on the flexible elongate device.

According to some embodiments, axial support structure 400 may be usedto support a relatively stiff elongate device that can be subjected tolarge axial loads during steering. For example, steering wide and/orthick-walled flexible elongate devices (e.g., a catheter with a largerouter diameter (OD)) may involve greater pulling forces than steeringnarrower and/or thinner-walled elongate devices. Whereas other types ofsupport structures may have difficulty withstanding the increased axialloads associated with wide and/or thick-walled devices, axial supportstructure 400 may be well-suited for such applications.

According to some embodiments, axial support structure 400 may be usedin applications where mechanical pushing (and/or pulling) is applied tothe flexible elongate device. For example, mechanical pushing may beapplied to force the flexible elongate device through a narrowconstriction in an anatomical passageway and/or to break through amembrane. Consistent with such embodiments, axial support structure 400may be used to bear the axial loads associated with mechanical pushingand/or pulling.

FIGS. 5A and 5B are simplified diagrams of an axially reinforcedflexible body 500 according to some embodiments. According to someembodiments consistent with FIGS. 1-4 , axially reinforced flexible body500 may be used to implement one or more sections of a flexible elongatedevice such as elongate device 202 and/or flexible body 216. In someexamples, axially reinforced flexible body 500 may be used to implementa steerable section of a flexible elongate device.

Axially reinforced flexible body 500 includes an axial support structure510 embedded in a pliable tube 520. According to some embodimentsconsistent with FIGS. 1-4 , axial support structure 510 may be aninstance of axial support structure 400. According to some embodiments,pliable tube 520 may be formed using heat shrink tubing. Consistent withsuch embodiments, although pliable tube 520 is depicted as having acircular cross-section, pliable tube 520 may conform to the shape ofaxial support structure 510 during heat shrink processing.

One or more lumens are defined through and/or alongside axial supportstructure 510. As depicted in FIGS. 5A and 5B, a primary lumen 532occupies a central portion of the channel of axial support structure510. According to some embodiments, primary lumen 532 may be the largestlumen in axially reinforced flexible body 500. For example, primarylumen 532 may extend to each of the four walls of axial supportstructure 510. In some examples, primary lumen 532 may be used for theinsertion and/or retraction of a medical instrument through axiallyreinforced flexible body 500. In some examples, primary lumen 532 mayaccommodate insertion and/or retraction of medical instruments with acircular cross-section.

A secondary lumen 534 and a pull wire lumen 536 extend through portionsof the channel of axially reinforced flexible body 500 that areunoccupied by primary lumen 532. Secondary lumen 534 and/or pull wirelumen 536 may be substantially narrower than primary lumen 532.Secondary lumen 534 and/or pull wire lumen 536 may generally occupycorner portions of the channel of axial support structure 510. Accordingto some embodiments, secondary lumen 534 and/or pull wire lumen 536 maybe formed by inserting a cable through axially reinforced flexible body500 prior to performing a heat shrink process and subsequentlywithdrawing the cable after the heat shrink process to cause a void inpliable tube 520 around secondary lumen 534 and/or pull wire lumen 536.Secondary lumen 534 may be used to insert a small medical instrument,electrical wires, fiber optic cables, and/or the like through axiallyreinforced flexible body 500. Although a single secondary lumen 534 anda single pull wire lumen 536 are depicted in FIGS. 5A and 5B, it is tobe understood that axially reinforced flexible body 500 may include anynumber of secondary lumens and/or pull wire lumens.

Axial support structure 510 includes a plurality of harnesses 542-548that form alignment guides running lengthwise through axially reinforcedflexible body 500. According to some embodiments, harnesses 542-548 maybe formed as push-in strips located in the corners of axial supportstructure 510. A particular alignment guide is made up of a set ofharnesses that are positioned at a same or similar cross-sectionallocations along the length of axial support structure 510. According tosome embodiments, the set of harnesses may be periodically spaced atfixed intervals axial support structure 510. For example, the fixedinterval may include every link, every other link, every fourth link,and/or any other suitable fixed interval. In some examples, the set ofharnesses may be spaced by irregular intervals.

According to some embodiments, the alignment guides formed by harnesses542-548 may be used to align secondary lumen 534 and/or pull wire lumen536 during formation of the respective lumens (e.g., during the heatshrinking process). For example, as depicted in FIGS. 5A and 5B,secondary lumen 534 extends along the top side of harness 542 and pullwire lumen 536 extends through harness 542. Harnesses 542-548 mayreinforce secondary lumen 534 and/or pull wire lumen 536 duringoperation. For example, harnesses 542-548 may prevent a pull wireinserted into pull wire lumen 536 from pulling through pliable tube 520into primary lumen 532 and/or secondary lumen 534. Harnesses 542-548 mayhold the pull wires in place to maintain steering alignment and/or toprevent the pull wires from drifting during operation, resulting in lossof steering control.

FIGS. 6A-D are simplified diagrams of a rigid link 600 for an axialsupport structure according to some embodiments. According to someembodiments consistent with FIGS. 1-7 , rigid link 600 may be used toimplement rigid links 411-419 of axial support structure 400 and/or 510.

Rigid link 600 includes a shaft 610 with a height ‘h’, a width ‘w’, alength ‘l’, and a thickness ‘t’. According to some embodiments, shaft610 may be formed from an extruded rectangular tube with a uniformcross-section. In some examples, shaft 610 may be made from stainlesssteel. In some examples, the height ‘h’, width ‘w’, and length ‘l’ mayeach be approximately 0.1 inches. In some examples, the thickness T maybe approximately 0.005 inches. Shaft 610 may optionally include one ormore holes 641-649 in various locations for purposes such as allowingheat shrink tubing to bind to shaft 610.

A set (e.g., a pair) of male joint connectors 620 and complementaryfemale joint connectors 630 extend lengthwise from opposite ends ofshaft 610. Male joint connectors 620 are affixed to one end of shaft 610and separated by a height ‘h’. Female joint connectors 630 are affixedto the opposite end of shaft 610 and rotated by 90 degrees in relationto male joint connectors 620. Female joint connectors 630 are separatedby a width ‘w’. Male joint connectors 620 include pins 625 (e.g.,convexities protruding from rigid link 600). Female joint connectors 630include pin receivers 635 (e.g., concavities or holes in rigid link600).

Male joint connectors 620 and female joint connectors 630 formcomplementary portions of a pin joint. When a plurality of rigid linksare coupled together to form an axial support structure, pins 625 of afirst rigid link fit into pin receivers 635 of a second rigid link toform a pivoting pin joint. The range of motion of the pivoting pin jointis determined in part based on how far male joint connectors 620 and/orfemale joint connectors 630 extend axially (i.e., along an axialdirection 660 of rigid link 600) from shaft 610. In some examples, malejoint connectors 620 and female joint connectors 630 may extendapproximately 0.02 inches lengthwise from the ends of shaft 610.

When ‘h’ is smaller than ‘w’, pins 625 are located on the outer surfaceof rigid link 600 and pin receivers 635 are located on the inner surfaceof rigid link 600. Conversely, when ‘h’ is larger than ‘w’, pins 625 arelocated on the inner surface of rigid link 600 and pin receivers 635 arelocated on the outer surface of rigid link 600. In some examples, pins625 and/or pin receivers 635 may be located on both inner and outersurfaces of rigid link 600 (e.g., pin receivers 635 may include holesthat extend from the inner to the outer surface of rigid link 600).

As depicted in FIGS. 6A-D, harnesses 652 and 654 are positioned onopposite corners of shaft 610. According to some embodiments, harnesses652 and/or 654 may include push-in strips (i.e., strips of shaft 610that are depressed inwards). According to some embodiments, harnesses652 and/or 654 may form alignment guides for one or more pull wires.Consistent with such embodiments, harnesses 652 and/or 654 may be usedfor aligning one or more lumens, such as pull wire lumens, duringmanufacturing. In some examples, harnesses 652 and/or 654 may be usedfor maintaining alignment of pull wires during operation and/or forreinforcing pull wire lumens to prevent pull-through into neighboringlumens and/or through the walls of the axial support structure.

Because rigid link 600 includes two harnesses 652 and 654 that arelocated in opposite corners of shaft 610, an axial support structureconstructed using rigid links 600 includes four alignment guides withharnesses alternating between pairs of opposite corners with each link.In some examples, however, rigid link 600 may include any number ofharnesses in any location or set of locations. In some examples, rigidlink 600 may include four harnesses, one in each corner, so that thealignment guides include harnesses on every link. In some examples,rigid link 600 may include a single harness so that the alignment guidesinclude harnesses every fourth link. In some examples, the harnesses maybe centered along the walls of shaft 610 rather than (or in addition to)being located in the corners. In some examples, the harnesses may belocated on an outer surface of rigid link 600, such that the alignmentguides run along the outside of the axial support structure. In someexamples, the harnesses may be shaped as hooks, tubes, ribbons, and/orthe like.

When coupling rigid links together to form an axial support structure,adjacent pairs of rigid links are rotated by 90 degrees relative to eachother to cause male joint connectors 620 to align with female jointconnectors 630 and form a pin joint, such as any of the pin joints421-429. The height ‘h’ and the width ‘w’ of shaft 610 are selected tofacilitate alignment between male joint connectors 620 and female jointconnectors 630. According to some embodiments, shaft 610 may have anoblong cross-section (i.e., h≠w), such as a rectangular or ellipsoidalcross-section. According to some embodiments, the height ‘h’ of shaft610 may be smaller or larger than the width ‘w’ of the shaft 610 by anamount corresponding to twice the thickness ‘t’ of the walls of shaft610 (i.e., h=w−2 t or h=w+2t). In such embodiments, male jointconnectors 620 and female joint connectors 630 may extend straight outalong axial direction 660 from shaft 610. On the other hand, in someembodiments, the height ‘h’ and width ‘w’ of shaft 610 may be the sameand/or otherwise may not be offset from each other by twice thethickness ‘t’. Consistent with such embodiments, male joint connectors620 and/or female joint connectors 630 may be shifted relative to thebody of shaft 610 (e.g., angled relative to axial direction 660) inorder to form a pin joint.

FIG. 7 is a simplified diagram of a method 700 for fabricating anaxially reinforced flexible body according to some embodiments.According to some embodiments consistent with FIGS. 1-6 , method 700 maybe used to fabricate axially reinforced flexible body 500 including anaxial support structure, such as axial support structure 400, and/orrigid links, such as rigid link 600. According to some embodiments,method 700 may include fabrication steps that tend to improve thereliability and/or manufacturability of the axially reinforced flexiblebody, such as laser cutting, laser welding, and/or the like. Bycontrast, method 700 may avoid fabrication steps that tend to diminishthe reliability and/or manufacturability of the axially reinforcedflexible body, such as braiding.

At a process 710, a plurality of rigid links are formed. According tosome embodiments, the plurality of rigid links may be formed from arectangular tube, such as an extruded rectangular tube of stainlesssteel. According to some embodiments, a single rectangular tube with auniform cross-section is used to form a plurality of rigid links.According to some embodiments, the plurality of rigid links are formedby laser cutting the extruded rectangular tube. The rectangular tube hasa height ‘h’, a width ‘w’, and a thickness T, where the height ‘h’ issmaller or larger than the width ‘w’ by an amount corresponding to twicethe thickness T. Each of the plurality of rigid links includes a shaftof length ‘l’, a set (e.g., a pair) of male joint connectors on an endof the shaft separated by the height ‘h’, and a set of female jointconnectors complementary to the male joint connectors on the oppositeend of the shaft separated by the width ‘w’. According to someembodiments, a plurality of holes are formed in the plurality of linksto facilitate heat shrinking. The plurality of rigid links may besubstantially identical to each other to facilitate high manufacturingthroughput and/or reliability.

At a process 720, pins are formed on the male joint connectors of theplurality of rigid links. The pins may be welded (e.g., laser welded)onto an inner or outer surface of the male joint connectors. Forexample, the pins may be welded onto the inner surface when ‘h’ islarger than ‘w’ and may be welded onto the outer surface when ‘h’ issmaller than ‘w’.

At a process 730, pin receivers are formed on the female jointconnectors of the plurality of rigid links. According to someembodiments, the pin receivers may include holes that extend from theinner to the outer surface of the female joint connectors, where theholes are sufficiently large to accommodate the pins. According to someembodiments, the pin receivers may include recessions in the inner orouter surface of the female joint connectors. The pin receivers may beformed by laser cutting.

At a process 740, one or more harnesses are formed on the plurality ofrigid links. The harnesses may be formed on one or more corners of theshaft of the rigid links (and/or may be centered lengthwise along theshaft). For example, each rigid link may include two harnesses locatedon opposite corners of the shaft. According to some embodiments, eachharness may be formed by cutting (e.g., laser cutting) slits in theshaft and pushing in the portion of the shaft between the slits. Forexample the slits may include a pair of parallel slits. The pushed inportion of the shaft juts into the channel of the axial supportstructure to form an alignment guide inside the channel.

At a process 750, the plurality of rigid links are coupled to form anaxial support structure. Each of the plurality of rigid links is rotatedby 90 degrees with respect to adjacent rigid links so as to align themale joint connectors and the female joint connectors of the adjacentrigid links. The pins of the male joint connectors are inserted into thepin receivers of the female joint connectors to form pin joints, whereeach pin joint pivots around an axis perpendicular to the axialdirection of the axial support structure. The plurality of rigid linksmay snap together to form the pin joints. The axial support structuremay include three or more rigid links (three rigid links couple to formtwo perpendicular pin joints, allowing the axial support structure toflex in any direction).

At a process 760, the axial support structure is encapsulated in apliable tube to form an axially reinforced flexible body. According tosome embodiments, the pliable tube may be a plastic and/or rubber tubethat is disposed around the axial support structure by heat shrinking.According to some embodiments, one or more cables may be insertedthrough the axial support structure prior to heat shrinking so that thepliable tube forms one or more lumens around the one or more cablesduring the heat shrinking process. For example, one or more cables maybe inserted at a location where a secondary lumen and/or a pull wirelumen is desired. The pliable tube may conform to the shape of the axialsupport structure, resulting in axially reinforced flexible body havingapproximately the same rectangular cross-section as the axial supportstructure.

In an alternative embodiment, it may be desirable to provide a jacketover the axial support structure that will provide protection and someaxial reinforcement but still maximize flexibility of the axial supportstructure. Thus according to some embodiments, one or more layers may beformed between the axial support structure and the pliable tubepreventing the pliable tube from melting and entering gaps in the axialsupport structure during a heat shrink process. The one or more layersmay be formed from a material with a high melting point such aspolytetrafluoroethylene (PTFE). A pliable tube may be disposed aroundthe plurality of layers by heat shrinking and conform to the axialsupport structure providing protection to the axial support structure aswell as some axial support resulting in an axially reinforced flexiblebody having approximately the same rectangular cross-section as theaxial support structure. However, since the pliable tube does not meltwithin gaps of the axial support structure, bending flexibility ismaintained. Additional embodiments providing for various layers within aflexible elongate device with an axial support structure is disclosed inU.S. Patent Application No. 62/535,673 (filed Jul. 21, 2017) (titled“Flexible Elongate Devices and Methods”) which is incorporated byreference herein in its entirety.

Although illustrative embodiments have been shown and described, a widerange of modification, change and substitution is contemplated in theforegoing disclosure and in some instances, some features of theembodiments may be employed without a corresponding use of otherfeatures. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. Thus, the scope of theinvention should be limited only by the following claims, and it isappropriate that the claims be construed broadly and in a mannerconsistent with the scope of the embodiments disclosed herein.

1-20. (canceled)
 21. A flexible elongate device comprising: an axialsupport structure, comprising: a plurality of rigid links coupled byjoints, wherein: each of the plurality of rigid links comprises: ashaft; a pair of first connectors extending axially from a first end ofthe shaft; and a pair of second connectors at a second end of the shaftopposite the first end, the pair of first connectors being complementaryto the pair of second connectors and being radially spaced relative tothe pair of second connectors by 90 degrees; wherein each of theplurality of rigid links is rotated by 90 degrees with respect toneighboring links among the plurality of rigid links, thereby aligningeach pair of first connectors with a neighboring pair of secondconnectors to form the joints; and wherein each of the plurality ofrigid links forms at least a portion of a plurality of lumens extendingthrough the axial support structure.
 22. The flexible elongate device ofclaim 21, wherein the plurality of lumens includes a primary lumenconfigured to receive an instrument extendable through the flexibleelongate device.
 23. The flexible elongate device of claim 22, whereinthe plurality of lumens further includes at least one secondary lumenand at least one pull wire lumen.
 24. The flexible elongate device ofclaim 23, wherein the at least one secondary lumen is configured toreceive at least one of an optical fiber or an electrical wire.
 25. Theflexible elongate device of claim 22, wherein the plurality of lumensfurther includes a plurality of pull wire lumens disposed radiallyoutward from the primary lumen.
 26. The flexible elongate device ofclaim 21, wherein the plurality of rigid links are substantiallyidentical to each other.
 27. The flexible elongate device of claim 21,wherein the plurality of rigid links are composed of stainless steel.28. The flexible elongate device of claim 21, wherein the plurality ofrigid links are composed of plastic or thermoplastic material.
 29. Theflexible elongate device of claim 21, wherein the plurality of rigidlinks do not include nitinol.
 30. The flexible elongate device of claim21, wherein each of the plurality of rigid links has an outer wallthickness of 1 mm or less.
 31. The flexible elongate device of claim 21,wherein the shaft has a rectangular cross-section.
 32. The flexibleelongate device of claim 21, wherein the shaft has an ellipsoidalcross-section.
 33. The flexible elongate device of claim 21, wherein theshaft has a circular cross-section.
 34. The flexible elongate device ofclaim 21, wherein the shaft has a width, a height, a length, and athickness, and wherein the pair of convex connectors are separated bythe height and the pair of concave connectors are separated by thewidth.
 35. The flexible elongate device of claim 21, further comprisinga pliable tube surrounding the axial support structure.
 36. The flexibleelongate device of claim 21, wherein the pair of first connectorscomprises pins and the pair of second connectors comprises pinreceivers.
 37. The flexible elongate device of claim 21, wherein each ofthe plurality of rigid links comprises one or more harnesses extendingfrom an outer wall, and wherein at least one lumen of the plurality oflumens extends through at least one harness of the one or moreharnesses.
 38. An axial support structure for a flexible elongate devicecomprising: a plurality of rigid links coupled by joints, wherein: eachof the plurality of rigid links comprises: a shaft; a pair of firstconnectors at a first end of the shaft; and a pair of second connectorsextending axially from a second end of the shaft opposite the first end,the pair of first connectors being complementary to the pair of secondconnectors and being radially spaced relative to the pair of secondconnectors by 90 degrees; wherein each of the plurality of rigid linksis rotated by 90 degrees with respect to neighboring links among theplurality of rigid links, thereby aligning each pair of first connectorswith a neighboring pair of second connectors to form the joints; andwherein each of the plurality of rigid links forms at least a portion ofa plurality of lumens extending through the axial support structure. 39.The axial support structure of claim 38, wherein the plurality of lumensincludes a primary lumen configured to receive an instrument extendablethrough the flexible elongate device.
 40. The axial support structure ofclaim 39, wherein the plurality of lumens further includes at least onesecondary lumen and at least one pull wire lumen.